Applicable standards may limit the electric current drawn by laundry treating appliances, such as a clothes washing machine, to a preselected threshold value, such as may be established by Underwriters Laboratories or the National Electrical Code. For example, the washing machine may be coupled into a 120 VAC circuit by a 15 amp power cord matching the circuit amperage. However, actual current draw may be limited to a lower amperage, e.g. 12 amps, resulting in a lower power output.
Contemporary washing machines include a multitude of electricity consuming components. Two of the greatest current drawing components are the motor and the resistive heater. The simultaneous operation of the motor and heater will typically require current draws in excess of the power cord threshold value, especially for 120V, 15 amp circuits commonly found in the United States, which can lead to a tripping of corresponding circuit breaker for the circuit. Even in countries with greater power cord threshold values, in order to maximize the heating rate to minimize the cycle time, there is still a tendency for the motor and heater to be selected such that their simultaneous operation exceeds the power cord threshold value.